{"apiVersion":"1.0","identifier":"CVE-2026-70656","description":"Checkmate is an open-source, self-hosted tool designed to track and monitor server hardware, uptime, response times, and incidents in real-time with beautiful visualizations. From 3.5.1 until 3.9.2, an authenticated admin or superadmin can set matchMethod to regex and place a malicious expression in the expectedValue field for advanced HTTP monitor matching. server/src/api/validation/monitorValidation.ts accepts the expression, and server/src/service/network/AdvancedMatcher.ts synchronously evaluates it against an attacker-controlled HTTP response body on the Node.js main event loop without a timeout or worker isolation, allowing catastrophic backtracking to freeze API endpoints, monitor checks, and WebSocket connections for all users. This issue is fixed in version 3.9.2.","publishedAt":"2026-08-21T18:16:50","lastModifiedAt":"2026-08-21T19:17:50","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-70656","cvssScore":4.9,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","epssProbability":0.00416,"riskScore":0.51,"affectedProduct":"Checkmate","affectedVersions":">=3.5.1,<3.9.2","vulnerabilityType":"Web app","operatingSystems":[],"links":{"self":"https://www.redsauce.net/api/cves/CVE-2026-70656","webPages":{"es":"https://www.redsauce.net/es/cves/CVE-2026-70656","en":"https://www.redsauce.net/en/cves/CVE-2026-70656","fr":"https://www.redsauce.net/fr/cves/CVE-2026-70656","pt":"https://www.redsauce.net/pt/cves/CVE-2026-70656","de":"https://www.redsauce.net/de/cves/CVE-2026-70656","sk":"https://www.redsauce.net/sk/cves/CVE-2026-70656","el":"https://www.redsauce.net/el/cves/CVE-2026-70656"},"source":"https://nvd.nist.gov/vuln/detail/CVE-2026-70656"}}